Download “Switch-On” Electronics - Cleveland State University

Electronics
Dan Simon
Cleveland State University
ESC 120
Revised August 28, 2010
Voltage
• Voltage is the amount of work needed to
move an electric charge
• High voltage in an electrical system is like high
pressure in a hydraulic system
• Common outlets in the United States:
120 Volts, 60 Hertz, alternating current (AC)
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Current
• Electric current: The flow of electric charge
(electrons), measured in Amperes
• One amp of current means a flow of one
Coulomb (6.241 × 1018 electrons) per second
 Amps = Coulombs / second
• High current in an electrical system is like high
rate of flow in a hydraulic system
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Power
• Power: The rate at which current flows,
measured in Watts
• Power is the product of voltage and current
 Watts = Volts × Amps
• Typical power consumption
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

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Air conditioner: 2000 W
Clock: 2 W
Television: 200 W
Light bulb: 100 W
Ohio’s average electricity cost:
12 cents per kW-hr
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Resistors
A resistor reduces the rate of flow of electric
current, measured in Ohms: V = IR
Example: If R1 > R2, then the current through R1
will be less than the current through R2
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Resistor Combinations
Series:
R = R1 + R2
Parallel:
R = 1 / (1/R1 + 1/R2)
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Potentiometer
Trimpot Adjuster
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Capacitors
Capacitors store electrical energy
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Transistors
Transistors can be used as electrically-controlled
switches. The current through the transistor is
proportional to the voltage applied to the base.
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Diodes
Diodes allow current to flow only in one direction.
Light-emitting diodes (LEDs) emit light.
The long lead connects to the positive voltage.
Current flow
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Solderless Breadboard
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Breadboard
Internal connections in orange
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Wire and Wire Strippers
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Multimeter
Measures voltage,
current, and resistance.
If you get unpredictable
readings, check the
battery!
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Power Supply
Regulated 5 Volt power
supply: “wall wart”
You need to cut off the
connector so that you can
connect the bare wires to
your breadboard
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Breadboard
Breadboard with connector posts, ready for
power supply connections
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LED Experiment
Resistor value should be at
least 400 ohms
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Potentiometer Experiment
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Motor Experiment
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Motor Experiment
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